scholarly journals Asymmetric Binary Frequency Shift Keying and its Frequency Attribute

2013 ◽  
Vol 765-767 ◽  
pp. 1236-1239
Author(s):  
Shi Kai Zhang ◽  
Jian Li Jin
Keyword(s):  
Frequency Shift ◽  
High Speed ◽  
Continuous Phase ◽  
Spectrum Efficiency ◽  
Frequency Shift Keying ◽  
Modulation Format ◽  
Shift Keying ◽  
High Speed Data ◽  
The Time Domain ◽  
High Degree

An innovative asymmetric binary frequency shift keying (ABFSK) modulation format is presented and studied both in the time domain and frequency domain. First, the modulation function is demonstrated, it shows a quasi-continuous phase attribute and an ability of high speed data modulation. Second, the domain attribute is studied; it has a high degree of energy centralization. Thus, a narrow occupied bandwidth can be achieved after a proper filtering. Then, the finite spectrum can be conserved to improve spectrum efficiency.

A New CPFSK Demodulation Approach for Software Defined Radio

2019 ◽  
Vol 28 (14) ◽  
pp. 1950243
Author(s):  
Kayol Soares Mayer ◽  
Candice Müller ◽  
Fernando Cesar Comparsi de Castro ◽  
Maria Cristina Felippetto de Castro
Keyword(s):  
Frequency Shift ◽  
Software Defined Radio ◽  
High Speed ◽  
Carrier Frequency Offset ◽  
Continuous Phase ◽  
Phase Detector ◽  
Approximation Formula ◽  
Frequency Shift Keying ◽  
Loop Filter ◽  
Shift Keying

This paper proposes a new coherent Frequency-Shift Keying (FSK) demodulation technique for software defined radio platform, based on a new Digital Phase Locked Loop (DPLL) architecture. The proposed DPLL addresses the frequency dependence on classic DPLL architectures found in the literature. In classical approaches, the loop filter constants are dependent on the frequency level of the FSK transmitted symbols. The proposed approach applies a simpler feedback loop, with a single integrator and a phase detector architecture based on the small-angle approximation [Formula: see text], which resulted in a DPLL totally independent of frequency. The proposed demodulator has been implemented in Very High Speed Integrated Circuits (VHSIC) Hardware Description Language (VHDL) and evaluated for continuous-phase frequency shift keying (CPFSK) and Gaussian minimum shift keying (GMSK) signals. For CPFSK signals, the demodulator has been evaluated for 2, 4 and 8 frequency levels, with modulation indexes [Formula: see text], [Formula: see text] and [Formula: see text], respectively. For evaluation of GMSK signals, several Gaussian filter bandwidths were considered. In addition, a brief analysis for 2-CPFSK and GMSK is presented over multipath and carrier frequency offset. Results show that the proposed method presents a significantly reduced bit error rate when compared to other coherent methods presented in the literature.

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